Serum progesterone in various species

Reference intervals determined in consultation with Drs. Cathy Gartley and Tracey Chenier, Theriogenology, OVC HSC.

Do not use SST blood collection tubes for endocrinology test submission.



Reference intervals


Progesterone (Note conversion factor 3.18 nmol/L = 1 ng/mL)

Canine - bitch, anestrus

            - spayed

<3.0 nmol/L

<1.5 nmol/L


Canine - bitch in season, prior to LH surge

            - following LH surge

<3-6 nmol/L


>3-6 nmol/L

Varies in bitches relative to LH surge

Canine - bitch, post-ovulation

> 11-12 nmol/L

Concentrations reflect those of pregnancy or pseudopregnancy.

Canine - bitch, prepartum, first stage of labour

<6.4 nmol/L


Feline – queen, anestrus or spayed

<1.5 nmol/L


Feline – queen, diestrus, day 15

31 - 130 nmol/L

Concentrations reflect those of pregnancy or pseudopregnancy.


Equine – estrus/anestrus

<3.2 nmol/L



Equine - diestrus/pregnant

6-65 nmol/L

Assay in current use does not react significantly with progestins produced in latter portion of pregnancy, therefore best suited for use in early pregnancy


Bovine - estrus

<3.2 nmol/L



Bovine - diestrus/pregnant

>3.2 nmol/L


Protein electrophoresis

Canine n = 13, feline n = 32, equine n = 15, clinically healthy adult animals; bovine n = 28, mid-lactation Holstein cows.